What Happens in the Primordial Soup
by Marvelicious
Summary: Set aproximately a really, really long time ago, both boys are bacteria. In which Sam has a large pilus, and Dean wants and exchange of genetic material. Bacterial sex? CRACK.


Lightning flashes overhead, striking the surface of the water before splitting into dazzling fragments. It's the perfect atmosphere, Dean thinks. He can practically taste the methane; he's got a feeling in his cytoplasm that just won't quit, because tonight is the night.

Flagella brush casually all over the puddle, bacteria jostling into one another in the crowd – all of them hoping to get lucky too. But Dean's got an outer membrane that was just made for pilus, and he does his best to show it off.

That's when he sees him.

More accurately, they're brought together by a convection current in the primordial soup, but the second Dean's flagella brush against his, he can see that the other bacterium's F-positive – he's got a huge load of genetic information just waiting for some lucky prokaryote.

"Hey, flagellate here often?" He asks, his own flagella working to turn him around, soft glistening structures that Dean can't seem to take his eyes off of. "I'm Sam."

"Yeah, actually. Sam." And then Sam is facing him, and Dean can't take his eyes off his incredible pilus. He's gotta be… the thing's at least 8 nanometers thick.

Dean can feel his cytoplasm ripple in response, "I'm umm, Dean. Nice to meet you."

"Like what you see?" Sam's flagella wriggle invitingly, brushing against Dean's in all the right places, his pilus just barely pressing into him when he comes closer. Sam grinds up against him, teasing. "Want this pilus in you, opening up your membrane all pretty for my episome?"

There's a tingly feeling in his unbound organelles, the feel of Sam's pilus against him practically driving Dean out of his ribosomes. He's never wanted anything more in all five hundred hours of his life. "Oh Carbon yes." He assures Sam, reaching out to caress the other bacterium's pilus with his own flagella and Dean doesn't miss the shift of his membrane with the sensation. "Give me some of that genetic material baby."

It doesn't matter that this is the first time he's ever gotten F-plasmid. It's like he's been waiting for this his entire life, and he knows exactly what to do. Dean guides Sam eagerly against his phospholipid bilayer, and he can feel the small tear as Sam thrusts inside, his fluid membrane shifting to allow for the intrusion.

"Oh yeah Dean, so good for me," Sam encourages. "So tight – bet I'm the only one, aren't I?" He thrusts in even further, until they're cell membrane against cell membrane, the slight current to the water around them doing interesting things to where they're conjoined.

Dean's never felt anything like it – he's so full, gripping Sam's pilus in his cytoplasm as they're rocked back and forth, the heads of their lipids rubbing against each other with every motion. And just when he thinks it can't possibly feel any better, Dean feels his lipids starting to shift along with Sam's, their membranes fusing together to bring them even closer.

"Oh god Sam." The bacterium is using a freaking enzyme. He can feel the relaxase helping the transfer, Sam's episome releasing its paired strand of DNA into their conjoined cytoplasm. Then it's slipping through the mating bridge between them, entering Dean.

"Yeah, take my DNA," He replies to Dean's gasp, membrane shuddering delicately as it closes back up against where Dean's is reforming as well. Sam draws back his pilus, and both of them let themselves be swept along by the currents for a moment or two, each enjoying the feeling of having only half of a whole plasmid, the bacterium beside them containing their complementary strand.

And then they both begin the task of completing the double stranded plasmid all over again, floating together in satisfied silence as their genetic material replicates.

"I don't know about you," Sam sighs finally, watching as Dean starts to sprout his own pilus, membrane bulging out obscenely, "but I definitely want to do that again."

Between the two of them, Dean thinks of all the possible genetic combinations that can possibly occur, all of the transfers it would take… At the rate they're going to go, they'll be living on land by next year. And yeah, he can certainly evolve with that.


End file.
